Drive apparatus



June 2, 1959 E. LiHALL 2,888,828

' DRIVE APPARATUS Filed Sept. :s, 1957 United States Patent O DRIVE APPARATUS Emery L. Hall, Hiusdale, Iil., assignor to Whirlpool Corporation, a corporation of Delaware Applcation September 3, 1957, Serial No. 681,672

Claims. (Cl. 74-2305) This invention relates to apparatus -for providing a friction drive to a drive be1t or the 1ike.

In belt drives Where a rubber belt or other member is driven from a pulley or other such device excessive slippage often occurs, particuiarly where the pulley is of small diameter. This excessive slippage not only tends to waste power and wear out the be1t but often Wil1 throw the belt from the pulley, especially Where the pulley is not provided With side flanges but is in the shape of an extension of a motor shaft or the like.

The present invention either eliminates entirely or materially reduces the above-mentioned difficulties. This is accomplished by providing a so1id polytrifluorochlorw ethylene friction member as a part of the friction drive apparatus. This polymer provides an increasing coeflicient of friction with rise in the temperature. if slippage occurs in the structure of this invention the frictional heat caused by the siippage increases the coefiicient of friction of the polymer. Thus the drive efficiency of the apparatus is increased even when initial slippage occurs.

One of the features of this invention, therefore, is to provide an mproved apparatus for a friction drive in which a friction member of polytrifluorochloroethylene is employed. Other features and advantages of the invention will be apparent from the following description of one embodiment thereof as shown in the accompanyiug drawings.

Of the drawings:

Figure 1 is a side elevational view, partially broken away, of a vacuum cleaner embodying the invention; and

Figure 2 is an enlarged vertical =sectional view of the belt contacting portion of the drive shaft.

The vacuum cleaner shown in the accompanying drawings comprises a casing normally supported for movement on front wheels 11 and rear wheels 12. The casing also has attached thereto supporting wheels 13 positioned rearwardly of the wheels 12, With these wheels 13 being normally spaced above the floor as illustrated in Figure 1, but contacting the floor when the cleaner casing 10 is rotated rearwardy about the rear wheels 12.

In order to propel the cleaner over a floor or other surface to be cleaned, the c1eaner has rotatably attached thereto a handle 14 held in a fitting 15 in the customary manner. A conventional fi1ter bag (net shown) is attachable to the rear 16 of the cieaner and suspended from the handle 14.

A motor fan unit 18 is positioned in the casing 10 by normal means. A motor shaft 19 on which the fan 17 Thus Patented June 2, 1959 ice is mounted extends forwardly from the fan 17 so as to be positioned above the rotatable brush 20. The shaft 19 drives the belt 21 to rotate the brush 20.

The rigid polytrifluorochloroethylene collar 22 is press fitted on the drive sha-ft 19 which is contacted by the be1t 21 and provides a high coefl'cient of friction for driving the bel: 21. If When the driving operation is first commenced there is excessive slippage this slippage Will cause a rise in temperature of the collar 22 which Will increase its coeficient of friction to the point where the belt 21 will be driven with increasing efliciency. Actual tests have shown that even when the shaft 19 rotates initiaily Without driving the be1t 21 the temperature rise in the collar 22 soon becomes great enough to increase its coeficent of friction to the point Where the belt 21 is grasped and driven by the rotating shaft and collar. 'Ihus the polytrifiuorochloroethylene friction member is instrumental in providing an eflcient friction drive structure for a drive member such as the shaft 19 and associated structure and a driven member such as the ordinary rubber drive be1t 21.

The polytrifluorochioroethylene, probably more proper- 1y called polytrifiuorornonochloroethylene, is a. rigid material containing three fluorine and one chlorine atom on each ethylene group. The preferred material has a molecular Weight of at least 75,000 and preferably of about 75,000-110,000 and is a rigid thermoplastic material.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the detaiis of description, unless otherwise specified, but rather be construed broad1y Within its spirit and scope as set out in the accompanying claims.

I claim:

1. Apparatus for providing a friction drive to a drive be1t or the like, comprising: a rotatable shaft; and a friction member thereon of rigid polytrifluorochloroethylene normally in driving contact With said belt.

2. Apparatus for providing a friction drive to a drive belt or the like, comprising: a rotatable shaft; and a friction collar around said shaft of rigid polytrifiuorochloroethylene normally in driving contact With said be1t.

3. The apparatus of claim 2 wherein said collar is press fitted on said shaft.

4. Apparatus for providing a friction drive between 9. drive mernber and a driven member, comprising: a friation member of polytrifluorochloroethylene attached -to one of said members and making frictional contact With the other member, said polytrifluorochloroethylene being capable of an increasing coefficient of friction With increasing temperature.

5. The apparatus of ciaim 4 wherein said friction member is attached to said drive member.

References Cited in the file of this patent UNITED STATES PATENTS 1,953,617 Kitto Apr. 3, 1934 2,039,461 Sparling May 5, 1936 2,437,3 62 Rockofi Mar. 9, 1948 2,701,971 Carter et al. Feb. 15, 1955 2,792,377 Miller May 14, 1957 

